Skip to Main navigation Skip to Left navigation Skip to Main content Skip to Footer

University of Minnesota Extension
www.extension.umn.edu
612-624-1222

Extension > Garden > Diagnose a problem > What's wrong with my plant? > Annuals and Perennials > Snapdragon > Leaves discolored white, yellow or pale green

Print Icon Email Icon Share Icon

Snapdragon > Leaves > Leaves discolored white, yellow or pale green

1 of 3
  • Powdery mildew 1
  • Powdery mildew 2
  • Powdery mildew 3

Powdery Mildew
Oidium sp.

  • Powdery, fluffy white spots and blotches on leaves, stems, and flower parts
  • Tiny black round spheres may be visible within white spots late in the season
  • Spots typically start on lower leaves but can spread to cover the entire plant
  • Severely infected leaves may be completely covered in white or grayish white fungi
  • In some cases, leaves become curled or twisted or turn yellow due to the infection
  • More information on Powdery Mildew
2 of 3
  • Two-spotted spider mites 1
  • Two-spotted spider mites
  • Two-spotted spider mites

Two-spotted Spider Mites
Tetranychus urticae

  • Active during summer, particularly abundant during hot, dry weather
  • Pale stippling appears on the upper leaf surface
  • Leaves are discolored off green to whitish, yellowish, or bronze
  • Premature leaf drop can occur
  • Visible webbing occurs on infected leaves when populations are high
  • Adults are tiny (1/50th inch long) and oval, greenish or yellowish with a dark spot on either side of the body
  • More information on Two-spotted Spider Mites
3 of 3
  • Downy mildew 1
  • Downy mildew 2

Downy Mildew
Pernospora antirrhini

  • Leaves turn pale green to yellow and may curl slightly downward
  • Downy white fungal growth on underside of leaves
  • Plants become yellow in color and stunted
  • Infected leaves prematurely drop from the plant leaving a barren stalk with few leaves
  • Disease favors cool, wet weather
  • More information on Downy Mildew

Don't see what you're looking for?

  • © Regents of the University of Minnesota. All rights reserved.
  • The University of Minnesota is an equal opportunity educator and employer. Privacy